Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
//package kattis;


import java.io.*;
import java.util.*;

public class A419 {
//codeforces #422
	
	public static void main(String[] args) throws IOException {
		IO io = new IO(System.in);
		int n = io.nextInt(), m = io.nextInt();
		int[][] mat = new int[n][m];
		int min = Integer.MAX_VALUE;
		int minx = -1;
		int miny = -1;
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				mat[i][j] = io.nextInt();
				if(min > mat[i][j]) {
					min = mat[i][j];
					minx = i;
					miny = j;
				}
			}
		}
		int count = 0;
		LinkedList<String> out = new LinkedList<String>();
		count += min*Math.min(n, m);
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				mat[i][j] -= min;
			}
		}
		for(int i = 0; i < n; i++) {
			if(mat[i][miny] > 0) {
				for(int j = 0; j < mat[i][miny]; j++) {
					out.add("row " + (i+1));
				}
				int sub = mat[i][miny];
				count += sub;
				for(int j = 0; j < m; j++) {
					mat[i][j] -= sub;
				}
			}
		}
		for(int j = 0; j < m; j++) {
			if(mat[minx][j] > 0) {
				for(int i = 0; i < mat[minx][j]; i++) {
					out.add("col " + (j + 1));
				}
				int sub = mat[minx][j];
				count += sub;
				for(int i = 0; i < n; i++) {
					mat[i][j] -= sub;
				}
			}
		}
		boolean fail = false;
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < m; j++) {
				fail = fail || (mat[i][j] != 0);
			}
		}
		if(fail) {
			io.println(-1);
		} else {
			io.println(count);
			if(n <= m) {
				for (int i = 0; i < min; i++) {
					for (int j = 0; j < n; j++) {
						io.println("row " + (j + 1));
					}
				}
			} else {
				for (int i = 0; i < min; i++) {
					for (int j = 0; j < m; j++) {
						io.println("col " + (j + 1));
					}
				}
			}
			for(String string : out) {
				io.println(string);
			}
		}
		io.close();
	}
	
	
	static class IO extends PrintWriter {
		static BufferedReader r;
		static StringTokenizer t;

		public IO(InputStream i) {
			super(new BufferedOutputStream(System.out));
			r = new BufferedReader(new InputStreamReader(i));
			t = new StringTokenizer("");
		}

		public String next() throws IOException {
			while (!t.hasMoreTokens()) {
				t = new StringTokenizer(r.readLine());
			}
			return t.nextToken();
		}

		public int nextInt() throws IOException{
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}
}
}